A study of package cracking during the reflow soldering process.

Modeling of Moisture Diffusion and Moisture-Induced Stresses in Semiconductor and MEMS Packages

“…The diffusivity and solubility are in general measured together through well-established moisture weight gain/loss tests [7]. Property data for various packaging polymers are available in the literature (see, e.g., [3,[8][9][10][11][12][13][14]). The majority of the reported data were obtained at low temperatures below 100 • C, where the standard procedure is routinely practiced.…”

“…Such cavities can be produced by defective manufacture and polymeric interface degradation during storage or severe operation. It is generally speculated that the pop-corning failure results from high vapor pressure developed inside the defective cavity during the reflow process [3]. In order to calculate moisture transport into the cavity, Kitano et al [3] and Tay et al [8] proposed modeling procedures that employed a recursive procedure considering the vapor pressure-induced cavity volume change.…”

“…It involves a moisture diffusion analysis and a subsequent stress analysis, where the combined effect of moisture and temperature distribution on the deformation is calculated [1]. Although moisture diffusion in polymers had been a classical research topic due to the impact of moisture itself on the state of polymers [2], the need to model moisture-related phenomena in complex structures arose quite recently, i.e., just a decade ago, as moisture-related issues such as pop-corning became important in semiconductor packages [3].This chapter describes recent progress in modeling of moisture diffusion and moisture-induced stresses in semiconductor and MEMS packages. It addresses both basic and practical aspects including (1) the theoretical background of moisture diffusion and hygroscopic swelling, (2) modeling schemes to solve moisture diffusion and combined hygro-thermo-mechanical stresses, and (3) validation of modeling schemes.…”

“…It involves a moisture diffusion analysis and a subsequent stress analysis, where the combined effect of moisture and temperature distribution on the deformation is calculated [1]. Although moisture diffusion in polymers had been a classical research topic due to the impact of moisture itself on the state of polymers [2], the need to model moisture-related phenomena in complex structures arose quite recently, i.e., just a decade ago, as moisture-related issues such as pop-corning became important in semiconductor packages [3].…”

Evaluation of Estimation Method for Thermal Fatigue Crack Growth Rate in Epoxy Resin Composites

“…Therefore, it is necessary (4) , (5) to examine the destruction of the epoxy resin due to the stress riser like the edge of the flaking off as the starting point. In many cases, because the thermal expansion coefficient of epoxy resin is greater than that of the molded internal structure, if thermal stress of the epoxy resin occurs, the stress is low and high at a high temperature and a low temperature, respectively, then the stress waveform and the temperature changes during the temperature cycling become opposite to each other.…”